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Foundation Problems With Home Additions

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Sooner or later, every house undergoes remodeling work. Sometimes, remodeling happens because rooms, especially kitchens and bathrooms, need updating. Other times, homeowners want to upgrade wall-to-wall carpeting with wood flooring, or adding ceiling fans, or installing skylights.

Expanding a home’s living space by building an addition is a remodeling category that deserves special attention. Rather than working within the existing “footprint” of a house, building an addition calls for a new foundation, which must be properly designed, constructed, and joined to the existing foundation. Given the small size of many older houses, it’s not uncommon to find houses that have been through such a remodeling process more than once.

Joining new to old can cause problems

It’s not uncommon for homes with additions to develop structural problems, especially foundation problems. There are a number of reasons for this. The contractor who builds the addition is usually not the contractor who built the house, so he may not be familiar with soil conditions that can cause foundation damage, such as expansive clay soils.

If the budget for the addition is tight, some contractors take shortcuts to ensure a profit –examples include placing footings at shallow depths, omitting steel reinforcement that can make the foundation stronger, and “scrimping” on gravel and drainage tile that helps move water away from the new foundation.

Water Intrusion

Other foundation problems that can come up with house additions include water intrusion because of missing or improper gutters and downspouts, and moisture issues related to dirt-floored crawl spaces.

Crawl space foundations are very popular for additions because they are inexpensive, and they can be built with minimal excavation. Unfortunately, many contractors choose to build crawl space foundations that are vented to the outside and have dirt floors. They then install fiberglass insulation between the floor joists of the crawl space. This construction technique is almost certain to result in excessive moisture that introduces mold into the living space above, corrodes ductwork and other HVAC components located in the crawl space, and degrades fiberglass insulation.

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